If you application is under an MVVM architecture, one possible reason for this behavior could be that your view model doesn’t implement the INotifyPropertyChanged
interface. Also, if your view models implements INotifyPropertyChanged, you need to call the RaisePropertyChange event in order to update the values of your bind controls.

In case you continue experiencing this behavior, it could be helpful if you could provide us with your repro sample (for example, uploading to
SkyDrive) of your solution, so that we can help you find out the cause.

We are having almost EXACTLY the same issue. Did you ever figure anything out on this topic? We suspect the problem lies somehow with the synchronous nature of the callbacks and the fact that we're listening on the UI Thread in order to update
the UI with the status message. But obviously we're not sure because we haven't gotten it working either.